Vickers microindentation toughness of a sintered SiC in the median-crack regime

Technical Report · Tue Jan 01 04:00:00 EST 1991

DOI:https://doi.org/10.2172/5239751· OSTI ID:5239751

Ghosh, Asish; Kobayashi, A S ^[1]; Li, Zhuang ^[2]; Henager, Jr, C H ^[3]; Bradt, R C ^[4]

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1. Washington Univ., Seattle, WA (United States). Coll. of Engineering
2. Argonne National Lab., IL (United States)
3. Pacific Northwest Lab., Richland, WA (United States)
4. Nevada Univ., Reno, NV (United States). Mackay School of Mines

The Vickers microindentation method for the determination of the fracture toughness of ceramics was investigated in the median crack regime for a sintered alpha SiC. The results are compared with fracture toughness measurements by conventional fracture mechanics technique and also with the reported indentation toughness for the low-load Palmqvist crack regime. Indentation toughnesses in the median crack regime vary widely depending on the choice of the specific equation which is applied. The indentation toughnesses are also load (crack length) dependent. A decreasing R-curve trend results, in contradiction to the flat R-curve that has been observed with conventional fracture mechanics techniques. It is concluded that the Vickers microindentation method is not a reliable technique for the determination of the fracture toughness of ceramics in the median crack regime.

• Research Organization: Pacific Northwest Lab., Richland, WA (United States)
• Sponsoring Organization: DOE; USDOE, Washington, DC (United States)
• DOE Contract Number: AC06-76RL01830
• OSTI ID: 5239751
• Report Number(s): PNL-SA-16927; ON: DE92000225
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360203* -- Ceramics
Cermets
& Refractories-- Mechanical Properties
42 ENGINEERING
420500 -- Engineering-- Materials Testing
CARBIDES
CARBON COMPOUNDS
CRACK PROPAGATION
CRACKS
FRACTURE PROPERTIES
HARDNESS
MATERIALS TESTING
MECHANICAL PROPERTIES
SILICON CARBIDES
SILICON COMPOUNDS
TESTING